Low saturated magnetic field bismuth-substituted rare earth iron garnet single crystal and its use

Abstract

A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 Å-12.510 Å by the liquid phase epitaxial method, and represented by a general equation: Gd.sub.x R.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.z Al.sub.w O.sub.12 where R denotes at least one element selected from the group consisting of yttrium (Y), ytterbium (Yb) and lutetium (Lu), and x, y, z and w are numerical values in the ranges 0.50≦y/x≦1.35, 1.40≦x+y≦1.90, 0.0≦w/z≦0.3 and 0.7≦z+w≦1.25. The magneto-optic optical switch or Faraday rotator constituted by the bismuth-constituted rare iron garnet is stably operable in a temperature range of -20° C. to 60° C. Because of the saturated magnetic field is 160 (Oe) or less, a magnetic field application device necessary to invert the magnetic field can be miniaturized.

What is claimed is: 
     
       1. A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 Å-12.510 Å by the liquid phase epitaxial method, and represented by a general equation:   Gd.sub.x R.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.x Al.sub.w O.sub.12     where R denotes at least one element selected from the group consisting of yttrium (Y), ytterbium (Yb) and lutetium (Lu), and x, y, z and w are numerical values in the ranges 0.50≦y/x≦1.35, 1.40≦x+y≦1.90, 0.0≦w/z≦0.3 and 0.7≦z+w≦1.25.   
     
     
       2. A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 Å-12.510 Å by the liquid phase epitaxial method, and represented by a general equation:   Gd.sub.x Y.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.z Al.sub.w O.sub.12     where x, y, z and w are numerical values in the ranges 0.50≦y/x≦1.35, 1.40≦x+y≦1.90, 0.0≦w/z≦0.3 and 0.7≦z+w≦1.25.   
     
     
       3. A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 Å-12.510 Å by the liquid phase epitaxial method, and represented by a general equation:   Gd.sub.x Yb.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.z Al.sub.w O.sub.12     where x, y, z and w are numerical values in the ranges 0.50≦y/x≦1.35, 1.40≦x+y≦1.90, 0.0≦w/z≦0.3 and 0.7≦z+w≦1.25.   
     
     
       4. A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 Å-12.510 Å by the liquid phase epitaxial method, and represented by a general equation:   Gd.sub.x Lu.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.z Al.sub.w O.sub.12     where x, y, z and w are numerical values in the ranges 0.50≦y/x≦1.35, 1.40≦x+y≦1.90, 0.0≦w/z≦0.3 and 0.7≦z+w≦1.25.   
     
     
       5. In a Faraday rotator containing a bismuth-substituted rare earth iron garnet single crystal, the improvement comprises the single crystal is that set forth in claim 1. 
     
     
       6. In a magneto-optic optical switch containing a bismuth-substituted rare earth iron garnet single crystal, the improvement comprises the single crystal is that set forth in claim 1. 
     
     
       7. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 0 .81 Y 0 .81 Bi 1 .38 Fe 4 .00 Ga 1 .00 O 12  and a thickness of 72 μm. 
     
     
       8. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 0 .65 Y 0 .85 Bi 1 .50 Fe 3 .85 Ga 1 .15 O 12  and a thickness of 82 μm. 
     
     
       9. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 1 .17 Y 0 .67 Bi 1 .16 Fe 4 .24 Ga 0 .76 O 12  and a thickness of 69 μm. 
     
     
       10. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 0 .85 Y 0 .86 Bi 1 .29 Fe 4 .00 Ga 0 .76 Al 0 .24 O 12  and a thickness of 61 μm. 
     
     
       11. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 0 .76 Yb 0 .71 Bi 1 .53 Fe 4 .20 Ga 0 .80 O 12  and a thickness of 73 μm. 
     
     
       12. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has a composition expressed by the chemical equation of Gd 0 .74 Lu 0 .71 Bi 1 .55 Fe 4 .22 Ga 0 .78 O 12  and a thickness of 69 μm. 
     
     
       13. A bismuth-substituted rare earth iron garnet single crystal according to claim 1, wherein it has composition expressed by the chemical equation of Gd 0 .72 Y 0 .44 Yb 0 .39 Bi 1 .45 Fe 3 .98 Ga 1 .02 O 12  and a thickness of 72 μ.